Trolley shoe



Jan. 115}, 1 932.

W. SCHAAKE TROLLEY SHOE Filed Feb. 28, 1931 INVENTOR h/l 0/7) 56/700/(6.

MU ATTORNEY Patented Jan. 19, 1 .582

! n srres WILLIAM SGHAAKE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING CGMPANY, A CORPORATION OF PENNSYLVANIA.

TBOLLEY SHOE Application filefiFebruary 28, 1931. Serial No. 518,947.

A more specific object of my invention is to-provide an improved trolley shoe which shall be capable of collecting currents of high values, shall resist corrosion and shall have a long life. I

I Other objects of the invention will be explained fully hereinafter or will be apparent to those skilled in the art.

For a fuller understanding of the nature and scope of the invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawings, in which: I

Figure 1 is a view, in side elevation, of a trolley shoe embodying my invention;

Fig. 2 is a view, in end elevation, of'the.

trolley shoe shown in Fig. 1; and

Fig. 3 is a sectional View, taken along the line IIIIII of Fig. 1.

Referring to the drawings, designates a trolley shoe, which comprises a one-piece body portion 11 in which an insert 12 is cast integrally. The shoe 10 may be of a shape well known in the art, suitable for mounting in a trolley harp (not shown) which is carried by a trolley pole (not shown). The body 11 is provided with a slot 13 for receiving a bolt to secure the shoe in the trolley harp.

It will be observed that the top of the body 11 is so shaped as to form a trough for receiving a trolley conductor. The insert 12 is so disposed at the bottom of the trough as to engage the trolley conductor when the shoe is in operation. The side walls 14 serve to retain the shoe in position on the trolley conductor. I

In the past, trolley shoes have usually been made of a copper alloy such as brass or bronze or other non-ferrous metal which is non-corrosive and also is a good conductor of electricity. However, a trolley shoe composed of these metals has a short life, because of the frictional wear between the shoe and the trolley conductor.

In attempting to overcome the above men tioned defect, trolley shoes have been constructed which severally comprise two sides made of a non-corrosive metal anda hard? metal tongue clamped between them to engage the trolley conductor. The hard-metal tongue .is usually made of a high-carbon steel. However, trol ey shoes constructed in this manner are expensive on account of the ma chining operations required in making and assembling the various parts. It has also beenfound that the heat generated during the operation of the shoe gradually causes the metal tongue to lose its hardness to such degree that it becomes worn away by friction. A trolley shoe, constructed in accordance with my invention, in which a nitrided steel insert is cast integrally in the body, as shown in the drawings, has proved to be more ethcient in operation and to have a longer life not be described in detail in this specification.

Briefly, it consists of heat treating a steel alloy containing a certain percentage of aluminum or molybdenum or a combination of the two elements. The piece of steel to be treated is placed in a sealed container and maintained at a temperature of from 500 to 7 00 G. Ammonia gas is circulated through the container during the process, which is continued for a period of time dependent upon the purpose for which the metal is to be used.

In this manner, the article is provided with a hard, adherent, tough and corrosion-resistant layeror coating of satisfactory thickness. Since the surface of the steel piece, thus treated, is'both hard and non-corrosive, it is particularly adapted for use as an insert member in a trolley shoe.

Also, since nitrided steel 18 not afiected by high temperatures, the insert 12 may be treated by the nitriding process and then cast in the body portion 11. In this manner, the cost of a trolley shoe, having a hard-metal insert, may be greatly reduced, as compared with a trolley shoe made according to the teachings of the prior art.

A trolley shoe constructed in the abovedescribed manner is efficient in operation and has an exceptionally long life. The nitrided steel insert 12, which engages the trolley conductor when the trolley shoe is in operation, has a hard surface which is not aliected by the heat produced by the friction between the shoe and the trolley conductor, and by the electric current flowing from the trolley conductor through the shoe. The wear which takes place in a trolley shoe is caused, primarily, by the material becoming soft, be cause of the heat generated during operation, and thereby wearing away rapidly. Since the nitrided steel insert is not affected by heat, it retains its hard surface and, therefore, is not Worn away by friction.

I do not desire to be restricted to the specific embodiment of my invention herein shown and described, since it is evident that it may be changed and modified without departing from the spirit and scope of my invention, as defined in the appended claims.

I claim as my invention:

1. A trolley shoe for engaging a trolley conductor comprising a body portion composed of one metal and an insert composed of a difi'erent metal and cast integrally in the body portion, said insert being disposed to engage the trolley conductor.

2. A trolley shoe for engaging a trolley conductor comprising a body portion composed of a relatively shoft metal and an insert composed of a relatively hard metal capable of withstanding a high degree of heat and cast integrally in the body portion, said insert being disposed to engage the trolley conductor.

3. A composite trolley shoe for collecting current from a trolley conductor comprising a relatively soft-1netal body portion and a relatively hard-metal insert cast integrally in the body portion, said insert being disposed to engage the trolley conductor.

4. A composite trolley shoe for collecting current from a trolley conductor comprising a relatively light-metal body portion and a hard-metal insert capable of withstanding a high degree of heat cast integrally in the body portion, said insert being disposed to engage the trolley conductor.

5. A composite trolley shoe for collecting current from a trolley conductor comprising a relatively soft metal body portion and a nitrided-steel insert cast integrally in the body portion, said insert being disposed to engage the' trolley conductor.

6. A composite trolley shoe for collecting current from a trolley conductor comprising a body portion composed of a non-ferrous metal and an insert composed of nitrided steel and cast integrally in the body portion, said insert being disposed to engage the trol ley conductor.

7 A composite trolley shoe for collecting current from a trolley conductor comprising a body portion composed of a copper alloy and an insert composed of nitrided steel and castintegrally in the body portion, said insert being disposed to engage the trolley condu'ctor.

8. A composite trolley shoe for collecting current from a trolley conductor comprising e a body portion composed of an aluminum alloy and an insert composed of nitrided steel and cast integrally in the body portion, said insert being disposed to engage the trolley conductor.

9. A composite trolley shoe for collecting current from a trolley conductor comprising a body portion composed of brass and an insert composed of nitrided steel and cast integrally in the body portion, said insert being disposed to engage the trolley conductor.

10. A composite trolley shoe for collecting current from a trolley conductor comprising a body portion composed of bronze and an insert composed of nitrided steel and cast inim tegrally in the body portion, said insert being disposed to engage the trolley conductor.

In testimony whereof, I have hereunto subscribed my name this 17th day of February,

\VILLIAM SCHAAKE. 

